Plasma and pituitary hormone changes and follicular development after unilateral ovariectomy in cyclic rats.
After unilateral ovariectomy of 4-day-cyclic rats, plasma FSH increased over control values for 6--12 h after the surgery regardless of whether unilateral ovariectomy was performed before or after 08:00 h on the day of dioestrus, after which time compensatory ovulation did not occur at the next oestrus. Pituitary content of FSH also increased from 6 h after unilateral ovariectomy. In contrast, plasma and pituitary levels of LH and prolactin were generally within the range of values of sham-operated rats. Treatment with pentobarbitone between 13:00 and 14:00 h on the day of pro-oestrus in rats unilaterally ovariectomized after 08:00 h on dioestrus delayed the next spontaneous ovulation by 1 day and was accompanied by a rise in plasma FSH concentrations for 24 h and a doubling in the number of ovulations from the remaining ovary. Follicle counts showed an increase in large healthy follicles (greater than or equal to 501 micrometers diam.) and a decrease in atretic follicles in pentobarbitone-treated rats. It is suggested that the FSH rise induces compensatory follicular development and decreases follicular atresia when there is sufficient time for follicles to develop before the LH surge.
D000818:Animals; D002369:Castration; D004971:Estrus; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D006065:Gonadotropins, Pituitary / Q000378:metabolism*; D007986:Luteinizing Hormone / Q000097:blood; D006080:Ovarian Follicle / Q000187:drug effects / Q000254:growth & development*; D010060:Ovulation / Q000187:drug effects; D010424:Pentobarbital / Q000494:pharmacology; D010902:Pituitary Gland / Q000378:metabolism*; D011247:Pregnancy; D011388:Prolactin / Q000097:blood; D051381:Rats
D006065:Gonadotropins, Pituitary; D011388:Prolactin; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D010424:Pentobarbital